Phosphate tightly associated with a molecule, e.g., a protein, has been known since the late nineteenth century. Since then, a variety of covalent linkages of phosphate to proteins have been found. The most common involve esterification of phosphate to serine, threonine, and tyrosine with smaller amounts being linked to lysine, arginine, histidine, aspartic acid, glutamic acid, and cysteine. The occurrence of phosphorylated molecules, e.g., proteins implies the existence of one or more kinases, e.g., protein kinases, capable of phosphorylating various molecules, e.g., amino acid residues on proteins, and also of phosphatases, e.g., protein phosphatases, capable of hydrolyzing various phosphorylated molecules, e.g., phosphorylated amino acid residues on proteins.
Protein kinases and phosphatases play critical roles in the regulation of biochemical and morphological changes associated with cellular growth and division (D""Urso, G. et al. (1990) Science 250:786-791; Birchmeier, C. et al. (1993) Bioessays 15:185-189). They serve as growth factor receptors and signal transducers and have been implicated in cellular transformation and malignancy (Hunter, T. et al. (1992) Cell 70:375-387; Posada, J. et al. (1992) Mol. Biol. Cell 3:583-592; Hunter, T. et al. (1994) Cell 79:573-582). For example, protein kinases have been shown to participate in the transmission of signals from growth-factor receptors (Sturgill, T. W. et al. (1988) Nature 344:715-718; Gomez, N. et al. (1991) Nature 353:170-173), control of entry of cells into mitosis (Nurse, P. (1990) Nature 344:503-508; Maller, J. L. (1991) Curr. Opin. Cell Biol. 3:269-275) and regulation of actin bundling (Husain-Chishti, A. et al. (1988) Nature 334:718-721).
Protein kinases and phosphatases can be divided into different groups based on either amino acid sequence similarity or specificity for either serine/threonine or tyrosine residues. A small number of dual-specificity kinases and phosphatases have also been described. Within the broad classification, kinases and phosphatases can be further sub-divided into families whose members share a higher degree of catalytic domain amino acid sequence identity and also have similar biochemical properties. Most protein kinase and phosphatase family members also share structural features outside the kinase and phosphatase domain, respectively, that reflect their particular cellular roles. These include regulatory domains that control kinase or phosphatase activity or interaction with other proteins (Hanks, S. K. et al. (1988) Science 241:42-52). Given the importance of protein kinases in regulating a variety of key cellular processes, in particular, cellular signaling processes, there exists a need for the identification of novel protein kinases as well as therapeutic and diagnostic methods featuring said kinases as well as modulators thereof.
The present invention is based, at least in part, on the discovery of novel nucleic acid molecules and polypeptides encoded by such nucleic acid molecules, referred to herein xe2x80x9cEukaryotic Protein Kinase-55053xe2x80x9d or EPK-55053. The EPK-55053 nucleic acid and polypeptide molecules of the present invention are useful as modulating agents in regulating a variety of cellular processes. Accordingly, in one aspect, this invention provides isolated nucleic acid molecules encoding EPK-55053 polypeptides, as well as nucleic acid fragments suitable as primers or hybridization probes for the detection of protein kinase-encoding nucleic acids.
In one embodiment, the invention features an isolated nucleic acid molecule that includes the nucleotide sequence set forth in SEQ ID NO:1 or SEQ ID NO:3. In another embodiment, the invention features an isolated nucleic acid molecule that encodes a polypeptide including the amino acid sequence set forth in SEQ ID NO:2.
In still other embodiments, the invention features isolated nucleic acid molecules including nucleotide sequences that are substantially identical (e.g., 60%, 65%, 70%, 75%, 76%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, or 99.9% identical) to the nucleotide sequence set forth as SEQ ID NO:1 or SEQ ID NO:3. The invention further features isolated nucleic acid molecules including at least 30, 35, 40, 45, 50, 75, 100, 125, 150, 175, 200, 250, 260, 300, 350, 372, 400, 450, 500, 550, 600, 615, 650, 700, 750, 800, 850, 900, 950, 1000, 1050, 1100, 1150, 1200, 1250, 1300, 1350, 1400, 1450, 1500, 1550, 1600, 1650, 1700, 1750, 1800, 1850, 1900, 1950, 2000, 2050, 2100, 2150, 2200, 2250, 2260, 2300, 2350, 2400, 2450, 2500, 2550, 2600, 2650, 2700, 2750, 2800, 2825, 2850, 2875, 2900, 2950, 2960, or 2970 contiguous nucleotides of the nucleotide sequence set forth as SEQ ID NO:1 or SEQ ID NO:3. In another embodiment, the invention features isolated nucleic acid molecules which encode a polypeptide including an amino acid sequence that is substantially identical (e.g., 60%, 65%, 70%, 75%, 76%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, or 99.9% identical) to the amino acid sequence set forth as SEQ ID NO:2. The present invention also features nucleic acid molecules which encode allelic variants of the polypeptide having the amino acid sequence set forth as SEQ ID NO:2. In addition to isolated nucleic acid molecules encoding full-length polypeptides, the present invention also features nucleic acid molecules which encode fragments, for example, biologically active or antigenic fragments, of the full-length polypeptides of the present invention (e.g., fragments including at least 10, 15, 20, 25, 30, 35, 40, 45, 50, 75, 100, 125, 150, 175, 200, 250, 300, 350, 400, 450, 500, 550, 600, 604, 650, 700, 710, 716, 720, 730, 740, 750, 760, or 770 contiguous amino acid residues of the amino acid sequence of SEQ ID NO:2). In still other embodiments, the invention features nucleic acid molecules that are complementary to, antisense to, or hybridize under stringent conditions to the isolated nucleic acid molecules described herein.
In a related aspect, the invention provides vectors including the isolated nucleic acid molecules described herein (e.g., EPK-55053-encoding nucleic acid molecules). Such vectors can optionally include nucleotide sequences encoding heterologous polypeptides. Also featured are host cells including such vectors (e.g., host cells including vectors suitable for producing EPK-55053 nucleic acid molecules and polypeptides).
In another aspect, the invention features isolated EPK-55053 polypeptides and/or biologically active or antigenic fragments thereof. Exemplary embodiments feature a polypeptide including the amino acid sequence set forth as SEQ ID NO:2, a polypeptide including an amino acid sequence at least 60%, 65%, 70%, 75%, 76%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, or 99.9% identical to the amino acid sequence set forth as SEQ ID NO:2, a polypeptide encoded by a nucleic acid molecule including a nucleotide sequence at least 60%, 65%, 70%, 75%, 76%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 97%, 98%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, or 99.9% identical to the nucleotide sequence set forth as SEQ ID NO:1 or SEQ ID NO:3. Also featured are fragments of the full-length polypeptides described herein (e.g., fragments including at least 10, 15, 20,25, 30, 35, 40, 45, 50, 75, 100, 125, 150, 175, 200, 250, 300, 350, 400, 450,500, 550, 600, 604, 650, 700, 710, 716, 720, 730, 740, 750, 760, or 770 contiguous amino acid residues of the sequence set forth as SEQ ID NO:2) as well as allelic variants of the polypeptide having the amino acid sequence set forth as SEQ ID NO:2.
The EPK-55053 polypeptides and/or biologically active or antigenic fragments thereof, are useful, for example, as reagents or targets in assays applicable to treatment and/or diagnosis of EPK-55053 mediated or related disorders. In one embodiment, an EPK-55053 polypeptide or fragment thereof, has an EPK-55053 activity. In another embodiment, an EPK-55053 polypeptide or fragment thereof, has a transmembrane domain, a eukaryotic protein kinase domain, a UBA domain, and, optionally, has an EPK-55053 activity. In a related aspect, the invention features antibodies (e.g., antibodies which specifically bind to any one of the polypeptides described herein) as well as fusion polypeptides including all or a fragment of a polypeptide described herein.
The present invention further features methods for detecting EPK-55053 polypeptides and/or EPK-55053 nucleic acid molecules, such methods featuring, for example, a probe, primer or antibody described herein. Also featured are kits for the detection of EPK-55053 polypeptides and/or EPK-55053 nucleic acid molecules. In a related aspect, the invention features methods for identifying compounds which bind to and/or modulate the activity of an EPK-55053 polypeptide or EPK-55053 nucleic acid molecule described herein. Further featured are methods for modulating an EPK-55053 activity.